As you all know I just love my IC buses. (not) Anyway, had the red circle with exclamation point in it come on and low coolant light. Coolant is between lines in resivor. Took to IC dealer because I thought it would be under warranty. Dealer gives it back to me saying coolant was low. I said no it wasn't they say yes it was. I said, well I see you next week. Anyway, drove the 25 miles back home and put it on the route. Driver gets 3/4 of the way done with pm route and the lights come on again. I told him to run it till it quits. Checked coolant, still ok. Any ideas. I'm really getting tired of these highly technical buses, aren't you?

Remember the good buses? Ya know, the ones with the all steel tank with no sight glass...carry a paint stir stick to check the coolant every day. Not good enough...must have idiot light! Must drive mechanic insane!

We've had the same problem when the light comes on and then we get out there to check the level and shes got plenty! The guys at the dealer said to plug and unplug the sensor to "reseat" the sensor... haha yeah... no dice... I do remember seeing their truck in our lot and splicing metal orifice tubes on the return hose to the top of the resivior, i guess to keep the coolant from foaming causing a false reading on the level sensor.. again only slightly helped. I went and just Air Vac'd all the ones with that problem to eliminate any and all air pockets just for laughs.. lol yeah its kinda a goofy problem :D

Try this!The following applies to I-6 EGR and 2007 MaxxForce® DT,9 and 10

If you are experiencing low coolant faults with a DT 466 EGR and MaxxForce® DT,9 and 10 engine and the coolant level is correct, perform the following steps:

NOTE: DuraStar vehicles built with an I6 EGR or a 2007 MaxxForce® engine they are equipped with a black surge tank there should be a restricted fitting in the EGR return line. DuraStar vehicles with a 2007 MaxxForce® engines that are equipped with a Black surge and has a white dot on the top of the tank the EGR return line fitting in the tank is restricted. DuraStar vehicles with a 2007 MaxxForce® engines that are equipped with a clear surge tank the EGR return line fitting in the tank is restricted.1.Verify that the coolant level is in the top of the upper sight glass or above the Max line on newer tanks, when the engine is warm.

2.If the level is below the top of the upper sight glass top off the surge tank to the proper level and see if the problem has been corrected, if not proceed to step 3.

3.If the coolant level is correct, the EGR deaeration line will have to be restricted by inserting a second 1/8 inch restriction into the line. Do not replace the surge tank. The fitting should be installed within 5 inches or 120 mm of the EGR cooler fitting. On MaxxForce® DT, 9 and 10 engines install a restrictor fitting in EGR deaeration line and the A/C bracket line a foot away from the surge tank.

Thanks for all your work, Bus Tech II!! I ended up bringing this back to the shop and letting it sit over night. The next morning the coolant indeed was low (just at low mark). Found leaking booster pump, replaced it and this solved the problem.

I guess I am overly sensitive on these ICs. I'm going to have to get it out of my head that every time a light comes on the dash that it's the emissions system malfunctioning. Although this is the first time I have had anything else wrong with this bus besides the emissions. lol I must say this has been a pretty good bus as far as ICs go. I still don't like that the windows stay open on one side and the dash is about to fall off before it's 3 years old but hey, they can't all be Blue Birds.

I've removed the boost pumps in about 60 of these with DT/EGR, MFDT, and MF7's and all the engine water pumps are up to the task of moving the coolant. I put one of those sweet pumps you mentioned ^^^ on an RE last month and it's pretty nice. The RE needed the extra boost; my CE's seem to get along fine without...

The kysor pumps changed their design from the pump with the moveable bottom copper fitting to a solid molded plastic bottom half... Eh I had two new ones crack in half, turns out they have the same problem as the old ones: if you check the wiring, once and awhile the wires are filpped and it spun the pump backward! They tried to correct it with a revision sheet in the box say to flip the wires in the connector! Well at least they are trying to make it last longer than the 5 minutes that they actually work without leaking :D

I've removed the boost pumps in about 60 of these with DT/EGR, MFDT, and MF7's and all the engine water pumps are up to the task of moving the coolant. I put one of those sweet pumps you mentioned ^^^ on an RE last month and it's pretty nice. The RE needed the extra boost; my CE's seem to get along fine without...

I have tried our V8 CEs with and without the booster pumps. Our heating circuits are plumbed series/parallel, in theory, half the coolant would flow to the right front heater and the other half to the heaters on the left hand side of the bus. Our booster pumps are on the Drivers side loop to promote coolant flow to drivers, defroster and underseat heaters. I feel we do better with the booster pumps and since our buses are nearly all parked outside we look for any advantage we might get.

The AT540-AT545 Allison's are a dark page in history books but with all the heat generated by the internal RPM oil slippage they did provide a fair amount of heat for the school bus heaters and defrosters.

My experience with Minnesota school buses from 1947 thru 1996 models. I found it ALWAYS better to have all heater/defrosters connected in one long series with the right front heater/defroster last as the coolant returned to the engine on the front engine chassis and NO booster pump was needed. In the 1980s and 90s I found 1/3 of my Blue Bird school buses with the heater hoses connected backwards to the engine.

The Bluebird problem was so bad that Thomas Brochures used multiple pictures to show how Thomas windshield defrosters cleared frost covered windshields very fast compared to Bluebird. When I contacted Bluebird engineering they didn't want to believe me but they called back a few hours later and stated that explained why all Thomas advertising also showed comparison diagram pictures of how Bluebird heaters and defrosters were plumbed backwards and not as good as Thomas.

The AT540-AT545 Allison's are a dark page in history books but with all the heat generated by the internal RPM oil slippage they did provide a fair amount of heat for the school bus heaters and defrosters.

My experience with Minnesota school buses from 1947 thru 1996 models. I found it ALWAYS better to have all heater/defrosters connected in one long series with the right front heater/defroster last as the coolant returned to the engine on the front engine chassis and NO booster pump was needed. In the 1980s and 90s I found 1/3 of my Blue Bird school buses with the heater hoses connected backwards to the engine.

The Bluebird problem was so bad that Thomas Brochures used multiple pictures to show how Thomas windshield defrosters cleared frost covered windshields very fast compared to Bluebird. When I contacted Bluebird engineering they didn't want to believe me but they called back a few hours later and stated that explained why all Thomas advertising also showed comparison diagram pictures of how Bluebird heaters and defrosters were plumbed backwards and not as good as Thomas.

Interesting story, Dwight! I hope I live long enough to say I've worked on over 50 years worth of school buses. 1996, in my opinion, was a great year for school buses. There was a lot of competition and the three majors had things down to a science. Now, with little competition and the cut throat world of school bus sales, we have little quality left. I do see it getting better but the reliability that was there in 96 doesn't exist anymore. Time will tell. Look forward to hearing more stories, Dwight!